Concerning Ethnic Differences on Intelligence Tests

Concerning ethnic differences on intelligence tests:

A) Asian-Americans score significantly higher than Whites, which accounts for the high proportion of Asian-Americans in technical occupations.
B) African-Americans tend to score lower than Whites, but researchers have not been able to identify why this disparity exists.
C) Hispanic-Americans have the lowest average test scores of any ethnic group.
D) Hispanic-American and Native American children tend to score lower on performance items as compared to verbal items.